Oldham Coupling Vibration Isolation in Roll Rotation Mechanism
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Solution Overview
Problem
Gear-type reduction mechanisms in roll rotation systems often cause vibrations due to angular transmission errors, leading to resonance and fluctuations in rotation rate, making it difficult to maintain a constant rotation speed during film winding.
Innovation Solution
A roll rotation mechanism that incorporates a gear-type reduction mechanism with a coupling shaft allowing movement about a central axis, blocking vibration transmission and preventing resonance, using an Oldham coupling to connect the drive-side and driven-side shafts, ensuring continuous constant rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a gear-type reduction mechanism is used to reduce motor rotation speed, then the roll can be rotated at a reduced rate, but vibrations occur due to angular transmission error causing resonance and rotation rate fluctuations
Solution Approach 1:
A coupling shaft is introduced as an intermediary component between the gear-type reduction mechanism and the roll. This coupling shaft has latitude of movement about its central axis, allowing it to absorb vibrations and prevent resonance while transmitting rotational motion, thus maintaining constant rotation rate despite the use of gear-type reduction mechanism
Solution Approach 2:
The coupling shaft is designed with specific degrees of freedom (latitude of movement about central axis) that change the dynamic parameters of the transmission system. This allows the system to tolerate angular transmission errors from the gear mechanism without transmitting vibrations to the roll, thereby maintaining stable rotation
2Power
If a wave gear reduction mechanism is used, then high reduction ratio is achieved, but the flexible external gear flexing causes inherent rotational fluctuations
Solution Approach 1:
The coupling shaft serves as a mediator that decouples the rotational fluctuations generated by wave gear flexing from the roll. By allowing latitude of movement about its axis, it absorbs the high-frequency vibrations from the flexing external gear while maintaining smooth rotation transmission
Solution Approach 2:
The coupling shaft is positioned in advance in the transmission path to cushion and absorb vibrations before they reach the roll. This preemptive cushioning prevents rotational fluctuations from being transmitted to the roll, ensuring stable rotation despite wave gear flexing
3Reliability
If traction drive-type reduction mechanism is used to achieve low rotational fluctuation, then constant rotation rate is maintained, but the mechanism is more expensive than gear-type reduction mechanisms
Solution Approach 1:
Instead of using an expensive traction drive mechanism, a simple coupling shaft with latitude of movement is introduced as an intermediary. This low-cost solution achieves the same vibration isolation and constant rotation rate maintenance that would otherwise require complex and expensive traction drive components
Solution Approach 2:
The coupling shaft provides a simple, inexpensive alternative to expensive traction drive mechanisms. This straightforward mechanical component achieves the desired vibration isolation without requiring complex, costly mechanisms, making the overall system more economical
4Device complexity
If belt/pulley-type reduction mechanism is used, then simple structure is achieved, but they cannot be mounted on roll rotating shaft in concentric state requiring external space
Solution Approach 1:
The coupling shaft is nested within the concentric arrangement of the gear-type reduction mechanism and roll shaft. This allows the vibration isolation function to be integrated into the existing concentric structure without requiring additional external space, combining multiple functions in a compact nested configuration
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The mechanism effectively blocks vibration transmission, preventing rotational fluctuations and allowing the roll to be continuously rotated at a constant rate without resonance, even when using a gear-type reduction mechanism.
Implementation Method 1
the coupling shaft does not have latitude of movement in the rotation direction, but is instead held in a state in which latitude of movement is present in a direction opposite the rotation direction, and rotational torque is transmitted. However, since latitude of movement is present, a vibration transmission path is blocked in a portion of the coupling shaft. Accordingly, vibrations are not transmitted from the gear-type reduction mechanism to the roll.
Data Source
AI summary
In a roll rotation mechanism (1) for continuously causing a film-rolling roll to rotate at a constant rate, an Oldham coupling (4) is interposed in a transmission path between a wave gear reduction mechanism (3) and a roll (10). The Oldham coupling (4) forms a connection between a gear rotation output shaft (34) and a roll rotation shaft (11) in a state in which latitude of movement α is present about a central axis line (4a). When a roll (10) is continuously rotated at a constant rate, the Oldham coupling (4) is held in a state in which no latitude of movement is present in a rotation direction R and latitude of movement α is present in a direction opposite the rotation direction; and rotation torque is transmitted. Due to the presence of the latitude of movement α, a vibration transmission path is blocked in the Oldham coupling (4), vibrations are not transmitted from the wave gear reduction mechanism (3) to a roll (19), a vibration system does not resonate, and no incidence of large rotational fluctuation occurs in the roller.